A light-sensitive material comprising a support and a light-sensitive layer containing silver halide, a reducing agent and a polymerizable compound is used in an image forming method. The image-forming method comprises image-wise exposing to light the light-sensitive material to form a latent image of silver halide, and developing the light-sensitive material to imagewise polymerize the polymerizable compound.
Examples of the image-forming methods are described in Japanese Patent Publications No. 45(1970)-11149 (corresponding to U.S. Pat. No. 3,697,275), No. 47(1972)-20741 (corresponding to U.S. Pat. No. 3,687,667) and No. 49(1974)-10697, and Japanese Patent Provisional Publication No. 57(1982)-138632, No. 57(1982)-142638, No. 57(1982)-176033, No. 57(1982)-211146 (corresponding to U.S. Pat. No. 4,557,997), No. 58(1983)-107529 (corresponding to U.S. Pat. No. 4,560,637), No. 58(1983)-121031 (corresponding to U.S. Pat. No. 4,547,450) and No. 58(1983)-169143. In the image-forming method disclosed in the above-mentioned publications, when the exposed silver halide is developed using a developing solution, the polymerizable compound is induced to polymerize in the presence of a reducing agent to form a polymer image. Thus, this method needs a wet development process using a developing solution. Therefore, the process takes a relatively long time.
An improved image-forming method employing a dry process is described in Japanese Patent Provisional Publications No. 61(1986)-69062 and No. 61(1986)-73145 (the contents of both publications are described in U.S. Pat. No. 4,629,676 and European Patent Provisional Publication No. 0174634A2). In this image-forming method, a recording material (light-sensitive material) comprising a light-sensitive layer containing a light-sensitive silver salt (silver halide), a reducing agent, a polymerizable compound and a binder provided on a support is imagewise exposed to light to form a latent image, and then the material is heated to polymerize within the area where the latent image of the silver halide has been formed. The above-mentioned image-forming method using a dry process is also described in Japanese Patent Provisional Publications No. 61(1986)-183640 and No. 61(1986)-188535.
There is also known an image-forming method in which the polymerizable compound is polymerized within the area where a latent image of the silver halide has not been formed, as described in Japanese Patent Provisional Publication No. 61(1986)-260241. In this method, the polymerization of the polymerizable compound within the area where the latent image of the silver halide has been formed is inhibited, and simultaneously the polymerization of the polymerizable compound within other area (i.e., area where the latent image of the silver halide has not been formed) is accelerated.
The image-forming method using the light-sensitive material having the above constitution generally comprises the steps of forming imagewise a polymer compound on the light-sensitive material, superposing the light-sensitive material on an image-receiving material having an image-receiving layer, and pressing them to transfer the unpolymerized polymerizable compound on to the image-receiving material so as to obtain a transferred image on the image-receiving material. In this method, preferably employed is a light-sensitive material in which the silver halide and the polymerizable compound are contained in microcapsules (referred to hereinafter as "light-sensitive microcapsule(s)"), as described in Japanese Patent Provisional Publications No. 61(1986)-275742 and No. 61(1986)-278849.
In the above-mentioned image-forming method, the density (maximum density) of the transferred image is sometimes low, and at that time, a sufficient density of the image can be hardly obtained. Particularly in the case of performing heat (thermal) development process for a long period of time, decrease of image density is frequently observed.